Two frontal brain regions, Anterior Cingulate Cortex (ACC) and Dorsolateral Prefrontal Cortex (DLPFC) appear to be particularly involved in attentional control and self-monitoring. There is evidence that while these regions work in tandem to regulate behavioral, DLPFC is specifically responsible for allocating attention to meet task demands, and ACC is specifically responsible for monitoring the stimulus processing and responding for performance difficulties and signaling the DLPFC and general arousal systems when reallocation of attention is needed. Important recent studies have revealed the complexities of the roles of these areas, and the need to understand their interactions. The four proposed experiments will use fMRI, EEG and behavior measures to address the following unresolved issues: 1) Whether ACC is involved in switching attention states, and whether separate subregions of the ACC are involved in the allocation of attention and in the detection of processing conflict, 2) How preparatory attention and performance monitoring functions interact, 3) What regions are responsible for reallocating attention to resole processing conflict, and 4) Whether the ACC or DLPFC are in error evaluation, and if so, whether these operations involve different subregions than preparatory attention and monitoring operations. This research will add to our understanding of the mechanisms that underlie dynamic behavioral control, and will inform the study of neurological disorders in which behavioral control is impaired, such as Schizophrenia, Alzheimer's Disease, Attention Deficit Disorder, and Obsessive Compulsive Disorder.